1. Field of the Invention
The invention relates to a document property detecting device, and more particularly, to a document property detecting device classified as document processing peripherals such as scanners and copiers.
2. Description of the Related Art
Accompanied with the rise of copiers, scanners, and multifunction peripherals during the recent years, people have gained convenience over document processing such as the copying, scanning, data storage, and sending of documents. Document processing has become a daily task for people, and therefore it is a vital issue as how to optimize the efficiency and convenience of document processing regarding to the design of multifunction peripherals.
During the document processing, it is important to get good control over the document size/location (generally called the document property). Take the flatbed scanner for instance, the document size and location have to be defined before scanning a certain area of a document. Therefore, a prior flatbed scanner is generally designed to prescan the entire flatbed to ensure the document size and location before proceeding with the actual scanning. However, the area of the document is usually smaller than that of the flatbed, hence scanning the entire flatbed lengthens the timing needed for scanning, thereby significantly lowering the efficiency of document processing.
A prior flatbed scanner 10 as indicated in FIG. 1 includes a cover 1 and a flatbed body 3. The cover 1 is provided with a platen 2. The flatbed body 3 is composed of a transparent glass 31, a light source 32 provided beneath the transparent glass 31, a plurality of photosensors 33 and a charge coupled device (CCD) 34. The photosensors 33 and the CCD 34 generally compose a CCD sensing module. It is to be noticed that the photosensors 33 are not necessarily be separated at a certain distance from the CCD 34 so that the CCD sensing module can be a minute sensing module. Further, the CCD sensing module can comprise a lens for focusing images within large areas to small areas. Therefore, the diagram is used merely for indicative purposes. During the scanning process in which the cover 1 covers the transparent glass 31 at the top of the flatbed body 3, the photo-signals from a document 4 or reflected by the platen 2 are received by photosensors 33 provided beneath the transparent glass 31, converted to electric signals, and sent out via the CCD 34. The electric signals are then converted to digital signals via an analog-to-digital (ACD) converter (not shown) and sent to the computer for processing. Hence the size and location of the document are confirmed, and further image scanning of the document can be proceeded. FIG. 2 is the plane figure from top view of the flatbed body 3 in FIG. 1, mainly showing the configuration of the photosensors 33 provided beneath the transparent glass 31. For the reason that the detection of size and location of the document is determined by the configuration of the photosensors 33, the number of photosensors has to be increased and the configuration thereof has to be restricted to accurately detect the size of the document. Consequently, this not only increases the production cost and brings difficulties in the design, but also results in the document detecting device being only able to detect standard document sizes such as A4 and A3.
In addition, other related techniques on document size detecting devices known are, a document size detecting device disclosed by the U.S. Pat. No. 5,321,273, in which the device employs a combination of a light emitting element, a spectroscope, lens and photosensitive elements to detect the document size; and an original document reading device capable of automatically detecting the size of an original document disclosed by the U.S. Pat. No. 5,500,725, in which the device uses distance sensors, a threshold value setting means, an original document size deciding means and a reading controlling means to detect the document size. It is then observed that prior document size detecting devices mostly employ the configuration of optical elements such as CCD photosensitive elements, photosensors and distance sensors to detect the sizes and locations of documents. However, as described above, these configurations of optical elements are prone to bring high production cost and design difficulties. Moreover, the light path configuration frequently results in increase in the volume or thickness of the flatbed body of the scanning device. Therefore, the present invention is intended to provide a document property detecting device that is able to overcome the aforesaid disadvantages, offer conveniences over its design, and detect the size and location of the document without prescan, thereby optimizing the efficiency of document processing.
Therefore, an object of the invention is to provide a document property detecting device that is capable of making the detection of document property more convenient by using the configuration of the transparent conductive substrate on the flatbed.
Another object of the invention is to provide a document property detecting device that is capable of detecting the document property without prescan.
Still another object of the invention is to provide a document property detecting device having conveniences over its design, thereby enabling the flatbed of the document property detecting device to be thin in volume.
The document property detecting device of the invention comprises a circuit including a first electrode and a plurality of second electrodes; a transparent conductive substrate for loading a document and electrically connected to the first electrode; and a cover with a plurality of conductive media electrically connected to the second electrodes. The cover further comprises a platen element on which the plurality of conductive media are fixed.
In a preferred embodiment of the invention, the transparent conductive substrate is substantially a transparent glass plated with a layer of transparent conductive film, which may be an indium tin oxide (ITO) film. Also, the conductive media are substantially a plurality of electrodes, or may be replaced by a plurality of electronic probes or a plurality of electronic sensors.
It is to be noted that, the conductive media in the invention may be simple electrode configurations, contact electronic probes or other conductive materials. The transparent conductive film plated on the transparent conductive substrate may also be any other transparent conductive film besides the ITO film. Because the document property detecting device of the present invention adopts a transparent conductive glass to load the document and employs conductive media to determine the document property by judging that whether or not the conductive media are in contact with the transparent glass, the document property detecting device has the following advantages:
1. the document property detecting device is capable of detecting the document property without prescan, thereby optimizing the efficiency of document processing,
2. the configuration and number of the conductive media may be easily controlled to accommodate the requirements of the designer, and
3. the document property detecting device is capable of detecting documents of non-standard sizes and punched documents.